Audio signals acquired from various sound sources may be synthesized with audio signals provided through a broadcast service such as a Television (TV) broadcast service, a radio broadcast service, or a Digital Multimedia broadcasting (DMB) service and accordingly, a single audio signal may be stored or transmitted. Here, a viewer may adjust an intensity of the entire audio signal, however, may not control characteristics of audio signals for each sound source, for example adjusting, for each sound source, intensities of the audio signals included in the entire audio signal. However, when audio signals for each sound source are independently stored, instead of being synthesized while writing content, the viewer may view a broadcast while controlling the intensities of the audio signals for each sound source using a terminal. As described above, an audio service enables multiple audio signals to be independently stored and transmitted in a storage/transmission unit, so that a viewer may listen to audio while properly controlling each audio signal in a receiver. The audio service is referred to as an object-based audio service.
In the object-based audio service, characteristics such as sound intensities of audio objects are defined as preset information, and may be utilized for playing back the audio signals. For example, in a Karaoke version song, a vocal with a low sound volume may be played back while sound volume of objects obtained by excluding the vocal from a preset remain unchanged, so that a user may use the Karaoke version song during singing practice. The preset information may typically be stored in a file, and the file may be transmitted. Accordingly, the preset information may be used to render various audio tracks stored in the same file.